This term is often used specifically to refer to the French Republican calendar time system used in France from 1794 to 1800, during the French Revolution, which divided the day into 10 decimal hours, each decimal hour into 100 decimal minutes and each decimal minute into 100 decimal seconds
https://en.m.wikipedia.org/wiki/Decimal_time
Oh, nice! It’s funny how it’s the same as the one I just made up which further proves that it simply makes sense.